• Journal of Periodontal and Implant Science
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• 제36권1호
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• pp.139-146
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• 2006

Many factors have been implicated in the etiology of gingival recession, including faulty toothbrushing, the position of the tooth in the arch(malalignment), the presence of inflammation, frenal attachment, impingement of restoration margins, orthodontic treatment and trauma from occlusion. Among the many factors, this study was to evaluate the relationship of occlusion and gingival recession. 640 teeth without other etiologic factors of gingival recession were evaluated in 40 subjects aged 21-59 years. Only 1st, 2nd premolar and molar were included in this study. We recorded nonworking contacts, working contacts, cervical abrasion, sex, gingival recession and evaluated that relation of occlusion and gingival recession. The results of this study were as follows; 1. Teeth with nonworking contacts were significantly more gingival recession than teeth without nonworking contacts.(p<0.01) 2. Teeth with working contacts were significantly more gingival recession than teeth without working contacts.(p<0.01) 3. Teeth with cervical lesion were significantly more gingival recession than teeth without cervical lesion.(p<0.01) 4. Men's teeth were more gingival recession than women's teeth but it was not significant.(p>0.01)

• 구강회복응용과학지
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• 제31권3호
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• pp.231-241
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• 2015

환자의 심미적 요구가 증가함에 따라 전치뿐만 아니라 구치부에서도 자연치아와 유사한 색조와 외형을 재현한 보철물에 대한 필요성이 증가하고 있다. 단일 지르코니아와 CAD/CAM 시스템을 통해 이러한 환자의 요구를 만족시키는 보철물 제작이 가능해졌다. 본 증례는 70세 여자환자로 전치부 보철물이 깨져서 보기 싫고 하악 구치부가 없어서 저작이 불편하다는 주소로 내원하였다. 하악 구치의 상실로 교합평면이 붕괴되었으며 과도한 치아 마모 및 수직고경 상실이 관찰되어 치아 상실 부위에 임플란트를 식립하고 수직고경 증가와 함께 지르코니아 고정성 보철물을 이용한 전악 수복 치료를 진행하였다. 치료 후 3년 간 이상적인 교합이 잘 유지되고 기능적, 심미적으로 만족한 결과를 얻었기에 이를 보고하는 바이다.

• The Journal of Advanced Prosthodontics
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• 제7권6호
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• pp.454-459
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• 2015

PURPOSE. To determine whether the fracture strengths and failure types differed between metal and zirconia frameworks veneered with pressable or layering ceramics. MATERIALS AND METHODS. A phantom molar tooth was prepared and duplicated in 40 cobalt-chromium abutments. Twenty metal (IPS d.SIGN 15, Ivoclar, Vivadent, Schaan, Liechtenstein) and 20 zirconia (IPS e.max ZirCAD, Ivoclar) frameworks were fabricated on the abutments. Each framework group was randomly divided into 2 subgroups according to the veneering material: pressable and layering ceramics (n=10). Forty molar crowns were fabricated, cemented onto the corresponding abutments and then thermocycled ($5-55^{\circ}C$, 10,000 cycles). A load was applied in a universal testing machine until a fracture occurred on the crowns. In addition, failure types were examined using a stereomicroscope. Fracture load data were analyzed using one-way ANOVA and Tukey HSD post-hoc tests at a significance level of 0.05. RESULTS. The highest strength value was seen in metal-pressable (MP) group, whereas zirconia-pressable (ZP) group exhibited the lowest one. Moreover, group MP showed significantly higher fracture loads than group ZP (P=.015) and zirconia-layering (ZL) (P=.038) group. No significant difference in fracture strength was detected between groups MP and ML, and groups ZP and ZL (P>.05). Predominant fracture types were cohesive for metal groups and adhesive for zirconia groups. CONCLUSION. Fracture strength of a restoration with a metal or a zirconia framework was independent of the veneering techniques. However, the pressing technique over metal frameworks resisted significantly higher fracture loads than zirconia frameworks.

• The Journal of Advanced Prosthodontics
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• 제5권2호
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• pp.187-197
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• 2013

PURPOSE. The purpose of this study was to evaluate various core designs on stress distribution within zirconia crowns. MATERIALS AND METHODS. Three-dimensional finite element models, representing mandibular molars, comprising a prepared tooth, cement layer, zirconia core, and veneer porcelain were designed by computer software. The shoulder (1 mm in width) variations in core were incremental increases of 1 mm, 2 mm and 3 mm in proximal and lingual height, and buccal height respectively. To simulate masticatory force, loads of 280 N were applied from three directions (vertical, at a $45^{\circ}$ angle, and horizontal). To simulate maximum bite force, a load of 700 N was applied vertically to the crowns. Maximum principal stress (MPS) was determined for each model, loading condition, and position. RESULTS. In the maximum bite force simulation test, the MPSs on all crowns observed around the shoulder region and loading points. The compressive stresses were located in the shoulder region of the veneer-zirconia interface and at the occlusal region. In the test simulating masticatory force, the MPS was concentrated around the loading points, and the compressive stresses were located at the 3 mm height lingual shoulder region, when the load was applied horizontally. MPS increased in the shoulder region as the shoulder height increased. CONCLUSION. This study suggested that reinforced shoulder play an essential role in the success of the zirconia restoration, and veneer fracture due to occlusal loading can be prevented by proper core design, such as shoulder.

• 대한치과의사협회지
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• 제51권4호
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• pp.190-197
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• 2013

A titanium based screw shaped dental implant was first introduced by Branemark and a treatment protocol where the restoration of edentulous area by connecting abutment after the osseointegration of the titanium surface of the implant and surrounding bone structure has been proposed. Although this protocol is widely accepted as a standard up to date, the healing duration of 3-6 months as well as the need for provisional prostheses during this period present as a major drawback. Immediate loading has been accomplished through the advent of various implant designs, enforced surface treatments, diverse forms of abutment, and delicate surgical techniques together with the increase in demand from the patients. The success rate of the immediate loading technique has been first reported as 85.7% by Dr. Schnitman in 1990 which recently has been reported up to 100% in the case of immediate loading in single tooth by Dr. Kan. To ameliorate the success rate of immediate loading technique, selection of patients presenting a sound bone quality and quantity, acquiring primary stability through delicate surgical techniques and fabrication of prostheses which accounts for biological stabilities should all be taken into consideration. This presentation introduces the understanding of biological stability of immediate loading, various methods for measurement of stability and clinical cases regarding immediate loading technique.

• Restorative Dentistry and Endodontics
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• 제42권2호
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• pp.146-151
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• 2017

X-linked hypophosphatemia (XLH) is a hereditary metabolic disease caused by the loss of phosphate through the renal tubules into the urine, and an associated decrease in serum calcium and potassium phosphate. Its dental features include spontaneous dental abscesses that occur in the absence of trauma or dental caries. The aim of this case report was to describe the dental problems of XLH patients and to evaluate limitations in their treatment. A 14 year old male and a 38 year old female with XLH were referred to the Department of Conservative Dentistry for endodontic treatment. The dental findings were periapical abscesses without obvious trauma or caries. Conservative endodontic treatment was performed in teeth with pulp necrosis and abscess. In case 1, the treated teeth showed improvements in bone healing, without clinical symptoms. However, in case 2, the implants and the treated tooth showed hypermobility, and the final restoration was therefore postponed. Early diagnosis, periodic examinations, and communication with the patient's pediatrician are important in the dental management of patients with XLH.

• Restorative Dentistry and Endodontics
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• 제26권1호
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• pp.32-40
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• 2001

The aim of this study was to evaluate the effect of various polymerization techniques on the microleakage of compomer restorations. Fifty extracted human premolars and molar were used and randomly divided into 5 groups. After cavity preparation, compomer (F2000$^{\circledR}$) was filled according to the manufacturer's directions. All groups, except group 5, were filled using an incremental technique. Group 1 was polymerized for 40 seconds at a continuous 485mW/$\textrm{cm}^2$ with a VIP$^{\circledR}$(Bisco, USA) light cure unit. Group 2 was polymerized for 20 seconds at 345mW/$\textrm{cm}^2$ and then for 20 seconds at 645mW/$\textrm{cm}^2$ with the VIP equation omitted light cure unit. Group 3 was polymerized at 400mW/$\textrm{cm}^2$, gradually increased to 50mW/$\textrm{cm}^2$ 10 seconds until 550mW/$\textrm{cm}^2$ was reached; total 40 seconds with a Spectrum 800$^{\circledR}$ (Dentsply Caulk, USA) light cure unit. Group 4 was polymerized for 3 seconds using an incremental technique with a Flipo$^{\circledR}$ (LOKKi, France) light cure unit. Group 5 was polymerized for 3 seconds using a bulk fill technique with the Flipo$^{\circledR}$ light cure unit. The specimens were embedded with acrylic resin, and were sectioned with diamond saws in a mesiodistal direction along the longitudinal axis of the tooth so as to pass through the center of the restoration, and three surfaces (occlusal, pulpal, and gingival) were examined with SEM. The results were as follows ; 1. Group 5 showed a significantly larger gaps compared to other groups on the gingival, occlusal, and pulpal walls. 2. All groups except group 5 had no statistically significant gap on the gingival, occlusal, and pulpal walls. 3. There was no significant correlation between the amount of enamel on the gingival and occlusal walls and polymerization shrinkage.

• Restorative Dentistry and Endodontics
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• 제18권1호
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• pp.215-226
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• 1993

Color stability of tooth colored restorative resins is an important factor, particularly in anterior teeth restoration. The purpose of this study was to evaluate the color stability and opacity change of several light curing composite resins. Specimens of eight composite resins(Prisma AP. H., Brilliant Enamel, Charisma, Durafil, Helio Progress, Herculite XR, P-50 and Silux Plus) were divided into two groups : In Group 1, the specimens were polymerized by visible light curing unit for 60 seconds on both sides and in Group 2, the post-cured specimens were heat tempered by light/heat curing unit for 45 units(about 18 min.). All specimens were stored in distilled water at $60^{\circ}C$ for 30 days. The color characteristics($L^*,a^*,b^*$) and opacity of the specimens before and after immersion were measured by spectrocolorimetry and the total color difference(${\Delta}E^*$) and opacity change (${\Delta}Y%$) were computed. The results obtained were as follows : 1. SP and APH in both groups, DF, HP and HXR in Group 1 showed ${\Delta}E^*$-value above 2.0. 2. DF, HP, SP and HXR in Group 1 showed higher ${\Delta}E^*$-value than in Group 2, but the others had no significant difference. 3. The opacity of CH and HXR in Group 1, and of CH and BE in Group 2 decreased after immersion, while that of the others increased. 4. Opacity change of BE, P50 and HXR was significantly different between Group 1 and 2. These results suggest that color change in the post-cure heat tempered specimens by light/heat curing unit was smaller than that of the specimens polymerized by visible light curing unit. No clinically detectable opacity changes were noted for any materials in either goup.

• Restorative Dentistry and Endodontics
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• 제23권1호
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• pp.304-315
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• 1998

The purpose of this study was to evaluate the microleakage of light cured glass ionomer restorative materials in class 5 cavities. In this in vitro study, class 5 cavities were prepared on buccal and lingual surfaces of forty extracted human premolars and molars on cementum margin. These specimen were randomly divided into four groups of 10 each : Group 1 was Fugi II (control), Group 2 was Fugi II LC, Group 3 was Vitremer, and Group 4 was Dyract. Group 2 was also divided once more into 2 groups of 5 each : Group 2-1 was pretreated with dentin conditioner and Group 2-2 was not. All teeth were restored according to the manufacturer's instructions. After 500 thermocycling between $5^{\circ}C$ and $55^{\circ}C$, the 40 teeth were placed in 2 % Methylene blue dye for 24hr, then rinsed with tab water. The specimen were embedded in clear resin, then sectioned buccolingually through the center of restoration with a low speed diamond saw. The dye penetration on each of the specimen were then observed with a stereomicroscope at 20. The results of the study were statistically analyzed using the Student-Newman-Keuls Methods and the Mann-Whitney Rank Sum Test. Tooth restorative interfaces were evaluated using SEM analysis. Results were as follows, 1. Compared to conventional glass ionomer restoratioqs, all light cured glass ionomer restorations were fairly resistant to microleakage (P<0.05). 2. Groups 3 (Vitremer) and Group 4 (Dyract) were found to be the most resistant, Group 2 (Fugi II LC) fairly resistant, and Group 1 (Fugi II) least resistant to microleakage(P<0.05). 3. No significant differences were found between Group 2-1 and Group 2-2 (P>0.08). 4. With the backscattered SEM analysis, the degrees to which tight bonding occurred were also observed in all the groups except for Group 1. Group 4 showed the highest degree of tight bonding than any other materials used in this study.

• 대한치과보철학회지
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• 제59권3호
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• pp.314-318
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• 2021

미만성 경화성 골수염(diffuse sclerosing osteomyelitis, DSO) 환자에서 임플란트를 사용하여 손실된 치아의 회복에 대한 보고는 거의 없다. DSO 환자는 임플란트의 골유착에 불리한 골질을 지니고 있기 때문에 임플란트를 식립할 때, 외과적 외상, 감염 관리 및 연장된 치유 기간과 같은 추가적인 고려사항이 필수적이다. 본 증례는 DSO 환자에서 임플란트 골유착의 실패와 성공에 관한 보고이다.